last update   10/23/17

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Mills Geological

High-quality, identified petrified wood and plant fossils from around the globe

Our Featured Specimen

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Mills Geological

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Beth and Jim

Primitive Conifer (Araucarioxylon arizonicum)

Chinle Formation, Petrified Forest Member, Triassic

Navajo/Apache Counties, Arizona

** Wow.  Gorgeous color in the “Goldilocks” size for this area – 5” in diameter and perfectly round.  This slab comes from the the same geologic formation as the the Petrified Forest National Park. Consequently, it has exactly the same mineralization as the deposits in the park that are called “Rainbow Forest beds,” an apt name for wood this colorful.  Rich reds predominate but the black and white accents make the whole thing truly a rainbow of color.  Petrified wood has long been collected on ranches outside the boundaries of the National Park but boundary changes for the expanding park have reduced those possibilities in the last decade. While collecting is still possible, the number of the best places producing beautiful wood like this one have been reduced.  We were delighted to be able to acquire this outstanding “Rainbow Wood” slab with excellent polish from an old collection.


5” in diameter on polished face; 7/16” thick slab   $59

Bald Cypress (Taxodium sp.)

Columbia Basalts Group, Miocene

Saddle Mountain, Washington

** So just what makes this specimen unusual enough to qualify for our “featured” spot?  Saddle Mountain wood is almost always beautiful, and this one certainly  is.  The colors in Saddle Mountain wood are almost always “wood-like” and attractive.  Check.  But this piece has something that is rather special.  It has several different “centers” (five of them by our count) but only one of them was dominant.  This was likely a strong limb (not a trunk) which had four different side branches and twigs which never got past an early age before being completely encapsulated by more rapidly growing xylem of the main limb.  The largest branch only achieved eight years of growth while the smallest of the group only achieved five years.  These kinds of features contribute to outstanding patterning in slabs of petrified wood and make them excellent display pieces.  If you already have a slab of this great wood from this locality, it may be time to upgrade or add an additional specimen!  Nice manageable size, warm autumnal colors.


Bald cypress occurs mainly along riparian wetlands subject to periodic flooding by silt-rich "brownwater" rivers.  The generic name is derived from the Latin word "taxus" meaning "yew" and the Greek word "eidos" meaning "similar to."  The trees are especially prized for their heartwood because it is extremely rot and termite resistant.  The heartwood of living trees contains a sesquiterpene called cypressene, which acts as a natural preservative.

7.5” x 5.5” on the polished face;  7/16” thick slab   $129

Redwood (Sequoia sp.)

Clarno Formation, Eocene

Private ranch between Madras and Antelope, Oregon

** A beautiful specimen from a private ranch near the intersection of Oregon Highway 293 and US 97 (about 15 miles north of Madras Oregon, just across the border in Wasco County).  At Tucson a few years ago, the firm named Russell-Zuhl had fantastic petrified sequoia tables made for conference rooms (I seem to recall that the tables were in the $70,000 price range).  The specimen we offer here came out of the same hole as the enormous 5-foot diameter log that was cut longitudinally into table tops.  There were only a few other small full rounds that came out of that hole, and they were left behind by Russell-Zuhl and eventually sold to an Oregon cutter.  We are fortunate to be able to offer a slab off of one of those very few other full rounds to come out of that hole.  This could have been either a root or a branch to that enormous log, but it is not possible to tell since the center of the round was destroyed by fungus and we cannot determine if there was a pith (indicating a branch) or no pith at all (indicating a root).

5” x 4” on polished face; 3/8” thick slab   $69

Conifer (Pinales Order)


Terrebonne, Oregon

** Unusual Locality!  Beautifully patterned slab from a locality not often seen on the petrified wood market.  The community of Terrebonne is located inbetween the Deschutes River and the Crooked River, approximately 20 miles south of the confluence of these two rivers.  Both of these two rivers have produced spectacular woods (Deschutes River to the north and Crooked River to the south) so a slab from Terrebonne would make a great link between those two petrified wood classics.  This is an unusual locality, so don’t miss a chance here!

10.5” x 5.75” on polished face; slab 5/8” thick   $179

Juniper (Juniperus sp.)

Toe Jam Creek Formation, Oligocene

Tuscarora, Nevada

** A phenomenal slab from a renowned locality with a humorous formation name!  The Tuscarora locality is famed for its brilliant shades of red, orange, gold – and its interesting patterns.  This slab is from an old collection.  How do we know that?  No one we know today is cutting slabs from logs this gorgeous at 1/2” thick!  All of the wood we have ever seen from Tuscarora is "squished" (a not-so-technical term) indicating that perhaps it was quite wet and spongy when it was buried under a great deal of volcanic ash. It is possible that the deposit might have been a pond with sunken logs in a "waterlogged" condition, making them susceptible to being compressed by the great weight of the ash into oval and diamond shapes instead of their original round configuration.  Part of the story that goes with this fabulous wood!

12" x 6" on polished face; 1/2" thick slab   $195

Conifer (Subclass Pinidae)

Indeterminate age

Southwestern Rub’ Al Khali, Najran Province, Saudi Arabia

** Unusual locality here! This interesting piece was collected several decades ago by an oil geologist working in Saudi Arabia.  It was found in a gravel plain between two Pleistocene-aged dune fields so he was unable to determine the actual age of the fossil wood itself.  There is just enough preservation that we could find some tracheids and determine that this was a conifer.  There simply is not a lot of wood from the Middle East on the American market, and even less from this unusual locality wherein the wood was transported in from some other distant location.  This is a locality almost guaranteed to be unrepresented in most collections!  If you like to have a wide diversity of localities in your collection, this is a good opportunity to add a new one!  It is a chunk off of what would have been a very much larger trunk and is cut on the transverse of the wood grain.

6” x 4” on the polished face; 1/2 inch thick slab   $45

Laurel Family wood (Laurinoxylon sp.)

Late Oligocene to Early Miocene, Mehama Volcanics in the Little Butte Formation

Sweet Home area, Willamette Valley, Oregon

** Highly attractive end cut of an interesting species.  The Lauraceae family is exceptionally large with 45 genera and over 2000 species.  Paleobotanists have thus erected the form genera Laurinoxylon for woods which share the characteristics of wood anatomy with the family but cannot be assigned to one of the many existing genera.  This specimen has very small vessels (under 50 microns in size) with most of them exhibiting vasicentric parenchyma.  It is a broadleaf evergreen (lacking growth rings). This specimen has some areas of really well-preserved wood anatomy structure, unlike a lot of Sweet Home material that cannot be identified at all.  The exterior length shows very aesthetic wood grain character along with encrustations of chalcedony.  A really nice specimen!

2.5” x 2” on polished face; 3.25” thick end cut   $30

Black Locust   (Robinia sp)

Grassy Mountain, Malheur County, near Vale, Oregon

Grassy Mountain Formation Early to Middle Pliocene

** Incredibly beautiful agatized specimen from the noted Grassy Mountain locality, which has arguably produced some of the most colorful specimens in the entire world.  Mustard yellow, bluish-gray, rust-red accents, punctuated by well defined growth rings.  The center is at the middle of the crescent at the six o’clock position. Please see our photomicrograph of the fantastic woody fine structure of this specimen.

5” x 4” on polished face; 1/4” thick slab   $65